Abstract: A sample aqueous stream including one or more organic compounds capable of partial oxidation to acid form are flowed continuously through an ultraviolet light reactor in which the sample is exposed to ultraviolet light in the presence of oxygen under conditions to partially oxidize the organic compounds to convert at least a portion of them to their corresponding ionized organic acids. Thereafter, the sample stream continuously flows through a conductivity cell in which the changing conductivity of the sample is detected as an indication of the presence of organic compounds in the sample stream.